The present invention concerns a supersonic nozzle, in particular for a turbojet engine.
The U.S. application of Hardy et al Ser. No. 336,491, filed 30 Dec. 1980, by the assignee of the present application, describes supersonic nozzles, each comprising essentially two annular systems of convergent flaps and divergent flaps which have their upstream edges hinged at the downstream edges of the convergent flaps. Actuating cylinders are distributed regularly about the duct outlet, and are coupled at appropriate points to every other convergent flap, so as to cause the position of at least every other divergent flap to vary with that of the corresponding convergent flap. Devices are shown for synchronizing the pivoting of the convergent flaps, so as to pivot with respect to the duct outlet.
Supersonic nozzles of known type, as will be pointed out, encounter problems of bulkiness and mass, in particular. Indeed, the total drag of the turbojet engine pod and, in particular, the so-called "base" drag, which has a strong influence on the performance of the turbojet engine, depends on the lateral moment of inertia of the nozzle itself. It thus would be desirable, in order to improve the performance of the turbojet engine, to reduce the lateral moment of inertia of the engine's supersonic nozzle. This result is, however, particularly difficult to arrive at because of the need to install the different devices required to control and synchronize the many flaps, (the actuating cylinders, rods, levers, etc.) between the stiffeners of the nozzle structure. Then there is a need for an arrangement to provide the necessary clearances for the different flaps and controls, as well as a need to retain a certain permeability within the assembly to permit adequate ventilation and, as a result, proper cooling of the different nozzle components. The present invention makes it possible to resolve all these problems, and to realize a supersonic nozzle of the type indicated that nevertheless is distinguished advantageously from previous realizations by a reduced lateral moment of inertia and total mass.